What Property Owners Need to Know About Nassau County's 2028/29 Tax Grievance Filing Period
Nassau County’s next property tax grievance
filing period opens January 4, 2027, and closes March 1, 2027. During that window, homeowners and commercial property owners may challenge the County’s tentative assessment for the 2028/29 tax year.
Although January may seem far away, the best time to begin reviewing an assessment is before the filing period opens. Determining whether a property is over-assessed may require reviewing the County’s property record, analyzing comparable sales, documenting the property’s condition or examining the income and expenses of a commercial property. Waiting until the final days of the filing period can make it more difficult to assemble a well-supported grievance.
The assessment challenged during this filing period will affect the school tax bill issued in October 2028 and the general tax bill issued in January 2029. That delay is one reason the Nassau County assessment process often causes confusion: the grievance is filed long before the resulting assessment appears on a tax bill.
Property owners who want to understand their options can learn more about our
Nassau County property tax grievance representation or request a complimentary assessment review.
What Is the Nassau County Tax Grievance Deadline for 2027?
The Nassau County Assessment Review Commission, commonly known as ARC, has announced the following schedule for the 2028/29 assessment:
- January 4, 2027: The Department of Assessment publishes the tentative assessment roll.
- January 4 through March 1, 2027: Property owners may file an application challenging the 2028/29 assessment.
- March 1, 2027: The filing period closes.
- March 31, 2028: ARC’s deadline for issuing final grievance determinations.
- April 3, 2028: The Department of Assessment publishes the final 2028/29 assessment roll.
- May 1, 2028: The deadline for seeking judicial review of the final assessment, including Small Claims Assessment Review where applicable.
Since filing dates can be extended or otherwise changed, property owners should confirm the deadlines using the
Assessment Review Calendar
and should not wait until the deadline to begin the process.
What Does a Nassau County Property Tax Grievance Challenge?
A tax grievance challenges the property’s assessment. It does not directly challenge the tax rates adopted by a school district, town, county or special district, and that distinction matters.
A tax bill can increase even when an assessment remains unchanged or is reduced because municipal budgets, school budgets, tax rates, exemptions and the distribution of the tax base may change. The relevant question in a grievance is whether the County’s assessment reflects a fair and lawful valuation of the particular property.
Nassau County permits applications challenging a property’s assessed value, its tax class, and the treatment of certain exemptions.
For most property owners, the central issue is value and whether the market value implied by the assessment exceed the property’s actual value as of the applicable valuation date.
Why Property Owners Should Start Reviewing Their Assessments Before January
The filing window is not the ideal time to begin investigating the property. A useful pre-filing review should address several separate questions, such as:
1. Is the County’s property information accurate?
Assessment records may contain incorrect information about living area, lot size, property classification, building characteristics or improvements. Even a seemingly minor error can affect the County’s valuation analysis.
Owners should compare the County’s records with reliable property documents such as surveys, certificates of occupancy, appraisals, floor plans and recent sale or mortgage documents. If the County’s physical description is inaccurate, the discrepancy should be identified and documented rather than merely asserted.
2. What market value does the assessment imply?
Nassau County applies a fractional level of assessment, meaning the number appearing as the assessment is only a fraction of the property’s asserted market value.
The meaningful comparison is between the market value implied by the assessment and the property’s actual fair market value. If the implied value is materially greater than the amount for which the property would reasonably sell, a grievance may be warranted.
3. What evidence supports a lower value?
For a one-, two- or three-family home, relevant evidence commonly includes recent arm’s-length sales of reasonably comparable properties. A useful comparison should account for differences in location, school district, living area, lot size, age, condition, renovations, waterfront access, traffic exposure and other features that influence value.
A recent arm’s-length purchase price may also provide important evidence. Property-condition issues can matter as well, particularly when a home requires substantial repairs or has functional limitations that are not reflected in the assessment record.
4. Does the property require a different valuation method?
Commercial, mixed-use, apartment and other income-producing properties generally cannot be evaluated in the same manner as a single-family home. Rental income, vacancy, operating expenses, lease terms, capitalization rates, zoning restrictions, environmental conditions and marketability may all affect value.
Owners of income-producing property should begin gathering rent rolls, leases, income and expense statements, vacancy information and other valuation material well before the filing deadline. Learn more about our
commercial property tax grievance representation.
A Prior Reduction Does Not Automatically Protect the Next Assessment
Nassau County establishes a new tentative assessment every year. A reduction obtained for an earlier tax year does not necessarily mean that the next tentative assessment will remain at the reduced level.
The Department of Assessment makes an independent annual valuation for all properties located in Nassau County. It is therefore possible for an owner to receive a reduction on a prior grievance and later discover that the new tentative assessment has increased again.
Property owners should review every new tentative assessment, even when they successfully grieved the property in a prior year, the prior grievance remains pending, the property has not been sold or renovated, or the owner did not receive a new assessment notice in the mail.
If an owner disagrees with the new assessment, a separate application must generally be filed for the new tax year. A pending application from an earlier year does not preserve the right to challenge a later assessment.
Do Nassau County Villages Have Separate Grievance Deadlines?
Many incorporated villages maintain separate assessment rolls for village taxes and often maintain different filing deadlines and timetable. A Nassau County grievance does not necessarily challenge a separate village assessment.
An owner whose property is located within an incorporated village should determine whether the village uses its own assessment roll, whether a separate grievance is required, the village’s applicable valuation date, and the village grievance deadline.
Village deadlines may differ from the County’s March 1st deadline. Owners should not assume that filing with Nassau County protects their rights concerning every assessment affecting the property.
Our firm represents property owners throughout the Towns of
Hempstead,
North Hempstead and
Oyster Bay, as well as the Cities of
Long Beach and
Glen Cove and Nassau County’s incorporated villages.
What Happens After a Nassau County Grievance Is Filed?
ARC reviews timely applications, supporting valuation material and settlement efforts are engaged in to effectuate a resolution of the administrative application. During this process, the assessment may be reduced or left unchanged--ARC does not increase an assessment as a determination of a grievance.
The review process is expected to extend through February of 2028, followed by the issuance of final determination letters by March 31, 2028. If the administrative grievance result does not provide sufficient or appropriate relief, the owner may pursue further review through Small Claims Assessment Review or an Article 7 tax certiorari proceeding, depending on the property and the circumstances.
Missing the original grievance deadline can also eliminate the right to seek judicial review. Timely administrative filing is therefore important even when an owner anticipates that further proceedings may ultimately be necessary.
Frequently Asked Questions About the 2027 Nassau County Filing Period
Can ARC raise my assessment because I filed a grievance?
No. Filing a grievance is not a basis for ARC to increase the assessment as its determination of the application, even if your property is under-assessed.
Do I need an attorney to file a Nassau County tax grievance?
No. Property owners may file their own applications through Nassau County’s AROW system or in certain circumstances, on the paper form. Attorney representation can assist with evaluating the assessment, selecting valuation evidence, addressing procedural requirements and determining whether additional review is appropriate.
Can commercial property owners file online?
Yes. ARC permits online filing for commercial and other property types, although the supporting valuation analysis and documentation may differ substantially from a residential grievance.
What if I did not receive an assessment notice?
Failure to receive a notice does not extend the filing deadline. Owners should independently check the tentative assessment after it is published.
Should I file again if last year’s grievance is still pending?
Yes. If you disagree with the new tentative assessment, a new application should generally be filed for the new tax year. Each annual assessment is a separate determination.
When will a successful 2028/29 grievance affect my tax bills?
The final 2028/29 assessment is scheduled to affect the school tax bill issued in October 2028 and the general tax bill issued in January 2029.
Request a Complimentary Nassau County Property Tax Review
Although the filing period will not open until January 4, 2027, property owners do not have to wait until January to determine whether their assessment deserves closer review.
Blodnick, Fazio & Clark represents homeowners, landlords, real estate investors and commercial property owners throughout Nassau County. Our Garden City office is located just a short walk from the Nassau County Assessment Review Commission, Department of Assessment and County Attorney’s Office.
We review the property’s assessment, available market information and relevant property records, explain whether a grievance appears warranted and handle the filing and review process for our clients.
Call our Garden City office at (516) 280-7105 or submit your property information to request a complimentary analysis. There is no legal fee unless we secure tax relief.
This article is for general informational purposes and does not constitute legal advice. Filing a grievance does not guarantee a reduction. Deadlines and procedures should be confirmed for the applicable tax year and municipality. Prior results do not guarantee a similar outcome. This website contains attorney advertising.
This blog was Reviewed by
Steven M. Fink, Esq., a New York property-tax grievance attorney with nearly 15 years of experience. Last updated September 2026.
